Projection optical device for microreaders capable of varying magnification

ABSTRACT

A microreader capable of varying the magnification of the information projected onto its viewing screen, having a projection lens system and a reflector system which are mounted on a drive system which moves them synchronously for scanning the information to be projected with a displacement ratio of 2:1, while also permitting movement of the reflector system independently of the projection lens system. The drive system consists of four fixed pulleys, and a movable pulley connected to the reflector system, all of which are suitably wound with a wrapping connector member. One of the fixed pulleys is connected to a drive means for driving the wrapping connector member and another of the fixed pulleys is connected to a device holding it against rotation but permitting adjustment of its position about its rotational axis. By connecting the projection lens system for movement with the driven pulley, it can be moved synchronously with the reflector system with the desired displacement ratio, and the reflector system can be moved independently by operation of the device adjusting the rotational position of the other pulley.

United States Patent [1 1 Yanagawa 51 Feb. 4, 1975 [75] Inventor: Nobuyuki Yanagawa,

Kanagawa-ken, Japan [73] Assignee: Ricoh Co., Ltd., Tokyo, Japan [22] Filed: Apr. 27, 1973 [21] Appl. No.: 355,021

Primary Examinerl-larry N. Haroian Attorney, Agent, or Firm-Cooper, Dunham, Clark, Griffin & Moran [57] ABSTRACT A microreader capable of varying the magnification of the information projected onto its viewing screen, having a projection lens system and a reflector system which are mounted on a drive system which moves them synchronously for scanning the information to be projected with a displacement ratio of 2:1, while also permitting movement of the reflector system independently of the projection lens system. The drive system consists of four fixed pulleys, and a movable pulley connected to the reflector system, all of which are suitably wound with a wrapping connector member. One of the fixed pulleys is connected to a drive means for driving the wrapping connector member and another of the fixed pulleys is connected to a device holding it against rotation but permitting adjustment of its position about its rotational axis. By connecting the projection lens system for movement with the driven pulley, it can be moved synchronously with the reflector system with the desired displacement ratio, and the reflector system can be moved independently by operation of the device adjusting the rotational position of the other pulley.

3 Claims, 5 Drawing Figures PATENTED FEB 41975 SHEET '4 BF 5 PATENTEU FEB 4 I575 SHEET 5 OF 5 PROJECTION OPTICAL DEVICE FOR MICROREADERS CAPABLE OF VARYING MAGNIFICATION BACKGROUND OF THE INVENTION This invention relates to projection optical devices for microreaders or other information card read-out apparatus, and more particularly it is concerned with a projection optical device which is capable of varying magnification.

In information card read-out apparatus known in the art, the optical system for projecting a frame of an information card, or a microfiche, for example, is fixed and an information card containing a number of frames is moved both longitudinally and transversely to bring any frame as desired to a position in which it is disposed in the optical path of the optical system. The apparatus of the prior art of the tyepe described have disadvantages. They require at least four times as much space as the space occupies by all the frames ofa single infor mation card for the information card to move in. As a result, the space required for the movement of the information card in the apparatus is too great; the mechanism for moving the information card is too complex; and the apparatus as a whole is too big in size to handle readily. T

In order to obviate these disadvantages, I have proposed to use an information card projection device of the movable optical system type in which any frame as desired of an information card can be positioned in the optical path of the optical system by moving the information card in one direction and moving the optical system in a direction at right angles to the direction of movement of the information card.

In this information card projection device of the movable optical system type, the lens means comprising a light source, condenser lens and a heat insulating filter and the reflector means are reciprocable in one direction while the two means are maintained in relation to each other such that the optical path length is constant at all times. This projection device has, however, the disadvantage of being unable to vary the size of projected images.

SUMMARY OF THE INVENTION The present invention provides an information card projection device of the movable optical system type which is capable of zooming and which can be made as compact as possible in size. This is accomplished by providing a device which permits the lens means and the reflector means to move conjointly while being maintained in predetermined relative positions to bring any frame of an information card as desired to a position in which it is disposed in the optical path of the optical system, and which thereafter permits the reflector means further to move independently of the lens means so as to vary the optical path length of the optical system andthereby vary the magnification of the optical device.

The projection device provided by the invention is capable of projecting any frame of the information card by varying the position of the optical path of the optical system and of varying magnification while maintaining the optical path between the screen on which an image is formed and one of the reflectors or the projection optic axis of the screen in a predetermined position at all times. 1

BRIEF DESCRIPTION OF THE DRAWINGS Other features and advantages of the invention will become evident from the description set forth hereinafter when considered in conjunction with the accompanying drawings, in which:

FIG. 1 is a side view of a device according to the invention;

FIG. 2 is a fragmentary sectional front view of the device;

FIG. 3 is a view in explanation of the drive means of the invention;

FIG. 4 is a view in explanation of an alternate embodiment of the invention; and

FIG. 5 is a view in explanation of the drive means for the device shown in FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION In FIG. 1, is shown a condenser lens system 2 of the type comprising a light source, a condenser lens and a heat insulating filter, and projectionlens system 5 comprising a projection lens 3 and first reflector 4 built therein as a unit. These systems, 2 and 5, are disposed on the same optical axis and juxtaposed to each other with an information card 1 or a microfiche, for example, being interposed therebetween. The projection lens 3 has a very small effective lens aperture of about 10 millimeters, so that the first reflector 4 may also be very small. Lens system 2 and 5 constitute the lens means of the present invention.

A second reflector 7and a third reflector 8 are arranged such that light reflected by the first reflector 4 may form an image on a screen 6. The screen 6 may be replaced by a printing surface when the device according to the invention is used with a printer, rather than as a microreader. The use of the three reflectors permits the screen 6 to be disposed near the lens system 2 and 5, thereby enabling the achievement of a compact size in a projection optical device. In FIG. 1, the first reflector 4 and the screen 6 are arranged such that the reflection optic axis of the former is substantially parallel to the projection optic axis of the latter.

FIG. 2 shows a support plate 9 for supporting the condenser lens system 2 thereon, provided with a slider 11 adapted to engage a slide guide main rail 10, and a roller 13 to move in rolling motion on an ancillary rail 12.

A support plate 14 for supporting the projection lens system 5 is provided with a slider 16 adapted to engage a slide guide main rail 15, and a roller 18 adapted to move in sliding motion on an ancillary rail 17.

A wrapping connector I9, such for example as a timing belt, wire or the like, is secured to the support plate 9 while another wrapper connector 20 is secured to the support plate 14.

As shown in FIG. 3, the wrapping connector 19 is trained over wheels 21 and 22 which may be pulleys or the like while the wrapping connector 20 is trained over wheels 23 and 24 which may also be pulleys or the like. The wheels 21 and 23 are mounted on a common drive shaft 25 so that they may function as drive wheels.

Lens system 2 and 5 are arranged such that their optic axes are aligned with each other, and are connected to the wrapping connectors 19 and 20, respectively, which move the same distances when the drive shaft 25 rotates, so that the lens systems 2 and 5 are maintained on the same optic axis while moving in a direction which intersects'the optic axis of the optical system. The drive shaft 25 may be rotated from a motor through a one revolution clutch 26 or the like.

When the lens systems 2 and 5 are moved, they are moved from one frame to another of the information card. That is, the drive shaft 25 is rotated through a unit angle of rotation by the one revolution clutch 26. When it is desired to move the lens means a distance corresponding to three frames of the information card, for example, the one revolution clutch 26 is actuated three times so as to rotate the drive shaft 25 through an angle which is three times as much as the unit angle of rotation. The clutch may be connected to the drive shaft 25 either directly or through a gearing or other suitable transmission system. A half-revolution clutch may, for example, be used in place of the one revolution clutch.

The drive shaft 25 has another pulley or a gear mounted thereon, such as pulley 27 shown in FIG. 3, whose diameter is the same as wheels 21 and 23. Pulleys 28, 29 and 30 which form a set with pulley 27 are fixedly disposed in the same plane. Another pulley 31 is arranged between pulleys 27 and 28 such that it is movable parallel to the line interconnecting the center axes of pulleys 27 and- 28. A wrapping connector 32, such for example as a timing belt, is trained about pulleys 27, 28, 31, 29, 30,31 and 27 in the indicated order to form a closed loop.

Pulley 31 (see FIG. 1) is rotatably supported by a support table 33 supporting the second reflector 7 and third reflector 8 in predetermined relative positions. The support table 33 (see FIG. 2) is supported by guide rails 34 and 35 for movement in the same direction as lens systems 2 and 5. The third reflector 8 is disposed such that it reflects light reflected by the second reflector 7 along an optical axis which is parallel to the optical axis of the first reflector 4.

A zooming dial 39 may be drivingly connected through bevel gear means, a slide shaft or other suitable mechanism to one of shafts 36, 37 amd 38 to which pulleys 28, 29 and are secured respectively.

Operation of the device according to the invention will now be described. When it is desired to set the optical system such that the projection light path is aligned with a predetermined frame of the information card, a drive motor isrotated and the one revolution clutch 26 is actuated. For example, when it is desired to move the lens means rightwardly in FIG. 1 a distance corresponding to four frames, the one revolution clutch 26 is actuated to make four revolutions so as to angularly rotate the drive shaft 25 through an angle which is four times as great as the unit angle of rotation. This causes pulleys 21 and 23 to rotate and move the wrapping connectors 19 and 20 a distance corresponding to four frames, thereby moving the lens systems 2, 5 rightwardly in FIG. 1 the same distance.

One of pulleys 28, 29 or 30 is locked in position when the zooming dial 39 is not manipulated. Thus, when the belt 32 is moved a distance corresponding to four frames by the rotation of the drive shaft 25, pulley 31 moves a distance which is one-half as great as the distance of movement of the belt 32. Being supported by the support table 33, reflector means 7, 8 also moves a distance which is one-half as great as the distance of movement of the belt 32. Since pulleys 21, 23 and 27 are of the same diameter and the belt 32 is trained over pulleys 27, 28, 29, 30 and 31 such that the lens means 2, 5 move in the same direction as the movement of pulley 3], rotation of the drive shaft 25 moves the reflector means 7, 8 in the same direction as the lens systems 2, '5 but the distance of movement of the former is one-half as great as the distance of movement of the latter.

Even though the lens means and the reflector means move as aforementioned, the optical path length from the lens system 5 to the screen 6 is unaltered. More specifically, while the lens system 5 moves a distance I on an optic axis 40 between the lens system 5 and second reflector 7, the second reflector 7 moves in the same direction as the lens system 5 a distance [/2 on the same optic axispOn the other hand. the third reflector 8 moves in the same direction as the lens system 5 a distance 1/2 on an optic axis 41 between the second reflector 8 and screen 6 so as to maintain the optical path length constant between thetwo reflectors 7 and 8 at all times. Thus the optical path length between the lens system 5 and screen 6 is maintained constant at all times.

When the lens systems 2, 5 are disposed in a projection position, and the desired frame of the information card is projected on the screen 6, it may be desired to enlarge or reduce the image of the frame formed on the screen 6. When this is the case, the zooming dial 39 is turned. Since pulley 27 is locked by the clutch 26 when the drive shaft 25 is not actuated, rotation of the zooming dial 39 sets pulley 28, 29 or 30 in motion, thereby moving pulley 31. This moves the reflector means 7, 8 while the lens systems 2, 5 and 6 remain stationary. Thus the second and third reflectors 7 and 8 move rightwardly in FIG. 1, so that the optical length of the optical system is increased and the image formed on the screen 6 is enlarged. Conversely, if the second and third reflectors move leftwardly, then the image is reduced.

The optical system according to the invention is arranged such that the optic axis 40 between the lens system 5 and second reflector 7 and the optic axis 41 between the third reflector 8 and screen 6 are parallel to each other. Thus the magnification can be varied by moving the second and third reflectors along their optic axes. Even if the reflectors are moved, it is possible to throw a picture of the predetermined frame of the information card on the screen without requiring to correct the position of the lens means or screen. Moreover, it is possible to obtain a compact size in a projection optical device comprising a mechanism for moving the lens means and reflector means.

The invention makes it possible to move the lens means and the reflector means by actuating the lens means drive mechanism while maintaining the optical path length constant, and to effect zooming by moving the reflector means independently of the lens means by manipulating the zooming dial either manually or by means of an electric motor.

The projection optical device is simple in construction and easily obtains dimensional accuracy, so that it lends itself to mass production.

In the embodiment shown and described, the wrapping connector system comprising pulleys 27, 28, 29, 30 and 31 and belt 32 is used for moving the reflector means comprising second and third reflectors 7 and 8. It is to be understood that the invention is not limited to the wrapping connector system described, and that an idle gearing or any other means may be used so long as it is possible to move the reflector means in the same direction as the lens means for a distance which is onehalf the distance of movement of the lens means.

FIG. 4 shows another form of drive mechanism for the optical system. As shown, the condenser lens means 2 and the projection lens means 5 are fixed as a unit to the bracket 50 which is secured at one side to a slider 52 guided in its sliding motion by a guide rod 51 and which rotatably supports at the other side a roller (not shown) adapted to move in rolling motion on a guide rail (not shown) so that the bracket 50 can reciprocate. Fixed to the slider 52 is a wire 53 which is trained over a pulley 54 mounted on a clutch (not shown), idle pulleys 55 and 56 supported for free rotation, a differential pulley 57 and pulley 54 in the indicated order to form a loop.

The reflector means comprising second reflector 7 and third reflector 8 is supported by a bracket 60 which is guided by a guide rod 61 for sliding reciprocating motion and which rotatably supports differential pulley 57 for reciprocating movement as a unit.

Idle pulley 58 is connected to a magnification adjusting dial (not shown) by suitable means.

In operation, the magnification adjusting dial is locked and consequently idle pulley 58 locked. Then the clutch is engaged to rotate pulley 54 so as to move the wire 53 and consequently the bracket 50 supporting the lens means a predetermined distance. Since idle roller 58 is locked, differential pulley 57 and consequently the bracket 60 supporting the reflector means move in the same direction as bracket 50 a distance which is one-half the distance of movement of bracket 50. Thus the distances of movement of the lens means and reflector means are at a ratio 1:0.5 at all times.

If idle pulley 58 is rotated by turning the magnifica tion adjusting dial while the pulley 54 mounted on the clutch is locked, then differential pulley 57 and consequently the bracket 60 supporting the reflector means moves. At this time. the bracket 50 supporting the lens means remains stationary. so that magnification of the optical system can be effected.

in the embodiment shown in FIG. 4, the lens systems 2 and 5 can be moved as a unit without the two systems being brought out of alignment with each other, thereby permitting the optical system to operate positively at all times. The embodiment shown in FIG. 4 is easier to control, more reliable in operation and simpler in construction than the embodiment shown in FIG. 1 to FIG. 3, because a single wire loop can drive the optical system. It is to be understood that the wire need not be an endless wire, and that it may be connected at opposite ends to the slider 51 to which bracket 50 is secured so that the wire may substantially function as an endless loop.

It is not essential that the magnification adjusting dial is connected to idle pulley 58. For example, an adjusting member may be secured to the run of the wire be' tween idle pulleys S8 and 59 for movement on a straight path. When this is the case, a linear calibration is used for indicating the degree of magnification. A knob connected to the adjusting member may extend out of the casing through a slot formed in the casing.

Other modifications will be apparent to oneof ordinary skill in the art without departing from the scope of the invention.

What is claimed is:

1. In a microreader of the type having:

a. a projection screen fixed with respect to a support;

b. information means containing an array of information to be read; and

c. optical means for projecting an information image from said information means onto said projection screen; the improvement wherein said optical means is capable of varying its magnification and comprises:

d. projection lens means mounted on said support for movement along said information means and including a first reflector for projecting the information image;

e. reflector means mounted on said support for movement in the same direction as said projection lens means and including second and third reflectors for receiving the information image projected by said first reflector and displacing and reversing the direction of the information image projection onto the projection screen; and

f. drive means for moving said projection lens means and said reflector means in synchronism with a displacement ratio of 2:1, said drive means comprising:

i. four pulleys fixed on said support;

ii. a movable pulley connected to said reflector means for movement therewith;

iii. wrapping connector means trained respectively about two of said fixed pulleys, said movable pulley and the remaining two fixed pulleys;

iv. means for rotating one of said fixed pulleys; and

v. means for fixing another one of said fixed pulleys against rotation and for adjusting its position about its rotational axis to permit movement of said reflector means independently of said projection lens means.

2. A microreader as in claim 1 further comprising:

g. guide rail means on said support for mounting said projection lens means for reciprocating sliding motion thereon; and

h. means for connecting said projection lens means to said wrapping connector means.

3. A microreader as in claim 1, wherein said projection lens means comprises:

i. a projection lens system; and

j. a condenser lens system; and said drive means further comprises:

k. guide rail means on said support for mounting said projection lens system and said condenser lens system for reciprocating sliding motion synchronously thereon; and

1. two sets of pulley means with respective wrapping connector means connected respectively to said projection lens system and said condenser lens system, each of said sets of pulley means being drivingly connected to one of said fixed pulleys. 

1. In a microreader of the type having: a. a projection screen fixed with respect to a support; b. information means containing an array of information to be read; and c. optical means for projecting an information image from said information means onto said projection screen; the improvement wherein said optical means is capable of varying its magnification and comprises: d. projection lens means mounted on said support for movement along said information means and including a first reflector for projecting the information image; e. reflector means mounted on said support for movement in the same direction as said projection lens means and including second and third reflectors for receiving the information image projected by said first reflector and displacing and reversing the direction of the information image projection onto the projection screen; and f. drive means for moving said projection lens means and said reflector means in synchronism with a displacement ratio of 2: 1, said drive means comprising: i. four pulleys fixed on said support; ii. a movable pulley connected to said reflector means for movement therewith; iii. wrapping connector means trained respectively about two of said fixed pulleys, said movable pulley and the remaining two fixed pulleys; iv. means for rotating one of said fixed pulleys; and v. means for fixing another one of said fixed pulleys against rotation and for adjusting its position about its rotational axis to permit movement of said reflector means independently of said projection lens means.
 2. A microreader as in claim 1 further comprising: g. guide rail means on said support for mounting said projection lens means for reciprocating sliding motion thereon; and h. means for connecting said projection lens means to said wrapping connector means.
 3. A microreader as in claim 1, wherein said projection lens means comprises: i. a projection lens system; and j. a condenser lens system; and said drive means further comprises: k. guide rail means on said support for mounting said projection lens system and said condenser lens system for reciprocating sliding motion synchronously thereon; and l. two sets of pulley means with respective wrapping connector means connected respectively to said projection lens system and said condenser lens system, each of said sets of pulley means being drivingly connected to one of said fixed pulleys. 